This proposal requests funds to assist in the support of the first biennial Gordon Research Conference on Hormonal Carcinogenesis to be held in the New Hampton School, New Hampshire, August 25-30, 1985. This meeting is to bring together a series of multidisciplinary experimental systems that are related by the common goal of understanding the carcinogenic activity of hormones at the cellular and organismal levels in endocrine organs and target tissues. This will provide an opportunity for a diverse group of life scientists to share their new ideas and data in informal discussion and enquiry during the week of this conference. The topics that provide this common ground are: (1) Etiology of human endocrine tumors - dealing with steroid and polypeptide involvement in human endometrial and breast cancer; (2) Cell proliferation - current studies on the role of steroid hormones, especially estrogens on growth of target cells in vitro, DNA synthesis, receptor binding, growth factors, etc.; (3) Cellular origin of endocrine tumors - dealing with current in vitro and in vivo studies on the cellular composition of the breast parenchyma and their relationship to the origin of hormone-dependent- and independent-tumors; (4) Steroid chemistry - dealing with modified steroids and their roles in carcinogenesis and in therapy; (5) Two sessions on Steroidal estrogen and Stilbene estrogen metabolism dealing with possible reactive intermediates; (6) One session on Structure activity relationships of estrogens in regard to receptor interactions and carcinogenic activity; (7) A session on animal models dealing with biochemical studies on estrogen-induced tumors and (8) A session on Estrogen-induced cell transformation in-vitro. We believe that this meeting should provide a forum not only for discussion of recent achievements in hormonal carcinogenesis, but should also add new influx and vigor to the field in terms of investigators, concepts, and experimental approaches which are essential for continued progress in this timely and significant research area.